I want to start using an airbrush to paint the uniforms on my figures and I was wondering what the ratio is when thinning down acrylics. Any help would be appreciated. Thank you.

Hi.....without knowing what experience you have with an airbrush....it is difficult to gauge your level of knowledge/skill/equipment....so forgive me if I over simplify my answer...
As a basic guide....start at 60% thinners t0 40% paint (Scale 75/Vallejo Game or Air)....this will vary if you use tube acrylics...which have a heavier body/pigment concentrate...
Remember this...don't mix the paint inside the cup of the airbrush...a lot of very experienced people do....trust me....the keyword is 'experienced'.....
As a visual guide follow this....once you have thinned to a ratio of 60/40....take a wide flat brush and load it with the thinned colour....draw this across the top side of the AB paint cup and see how the paint flows down the inside...
If it runs down slowly = too thick
Runs down very quickly...but you can see the metal through the paint trail = too thin
Flows quickly/smoothly with no metal showing through = good to go....

A couple of hints....for the paints I mentioned...use a 'psi' of 24 - 28.....watch for 'pooling/puddles on the surface = too thin/close.....spitting = too thick/too low (psi)...
Although basic....this should get you off to a good start....if you have any more questions please ask.

Regards

Ron

Hi Carl,
I can concur with Ron's explanation above it does work very effectively, I should know he only told me 500 times before it sunk in.
cheers
Richie

Thank you for the advice, I'll let you know how I get on.

The best advice is to not dilute the acrylic but with a specific thinner : the result has no comparison.
I use the Vallejo Airbrush Thinner

Hi Thierry-just to clarify.....are you saying that it is best to dilute each paint with the one provided by the manufacturer.

I'm about to have ago at Airbrushing myself so this advice is very useful

Claude

Hi Claude...
No but What I can say is that if you dilute the acrylic with water it won't work very well. Then, based onmy experience :
- Vallejo paint work very well with airbrush and even more with Vallejo air thinner (andrea colours and scale 75 are already a little bit thick... but you can dilute those with Valejo Air thinner, th paint composition is the same for those brands
- most important is to use the compressor at low pressure
- get a double action airbrush and work with small opening

hope this helps

In my experience....when working with acrylics....bottle or tube....any of the 'branded' thinners will work equally well....Vallejo/LifeColor/Scale 75/Ultimate et al....
If you use just water...the surface tension is too great...which prevents the paint from flowing and settling in a smooth/even film....it's the additive in 'branded' thinners that breaks down the surface tension....
If I run out of thinners.....I add a few drops of IPA (alcahol)...which does the same thing....
Be aware....too low a pressure..and you will get 'spitting'....no matter how thin the paint is!

Thanks for clarifying guys-much appreciated.

Claude

I found this video on making your own thinner with IPA very useful

all i can add is if you are using vallejo use vallejo products for thinning as stated above . i believe all acrylic paints have a learning curve but when you get around it they spray great . vallejo also has airbrush ready paints depending on the color they also may need a bit of thinner .

May I ask what, if any effect the thinners have on the paint, e.g. will it still dry to a matt finish?

Steve

Not an easy question to answer.....the short answer would be very little other than to make it flow better.........the longer explanation would be....
Acrylics are partly water....the thinners are designed to break down the 'surface tension' of the water...which increases the 'flow' properties of the paint...
This allows you to create a thinner layer of paint....which in turn means you can build it up to your desired density by adding more layers....
Conversely.....by having thinner layers...you can utilise the translucency of the thinned paint...to allow the undercoat/base colour....to show through.....

The acrylics I apply with the airbrush are primarily Tamiya. They are formulated for airbrushing, and I have learned to use their proprietary thinner, for the best results.

I have also used craft store acrylics, Apple Barrel and Americana, thinned with water. That worked well enough with those paints, but the paints themselves aren't very good for airbrushing, in my opinion, because their pigments are relatively coarse.

I'm not sure that the thinner will have anything to do with making the dried and cured finish matte. I have applied matte acrylics and gloss acrylics. The thinner did not make the gloss acrylics dry to a matte finish.

I usually brush at 20 psi, and with a ration of about 60/40 paint to thinner. However, as the others have noted, pressure and the thinning ratio may vary, depending on the job and the effect you're trying to achieve. As far as the thinning ratio goes, one common rule of thumb is "thinned to the consistency of skim milk." Well, I don't drink skim milk, I drink whole milk, and in any case, I can't tell the difference in consistency between skim milk and whole milk on site, I'd have to drink it. So that image has always been useless to me. I mix the paints right in the cup on my airbrush, and so, I eyeball it. I decant the paint from the jar into the cup, and then add the thinner with an eyedropper, estimating the ratio.

The best thing to do is to experiment and practice, and note what you do, and how it comes out.

Hope that helps, prost!
Brad